DE 100 64 356 A and DE 102 56 744 A describe combine harvesters that can optionally operate in a straw deposit mode and a chopping mode. In the chopping mode, the straw is guided through the straw chopper, and in straw deposit mode it bypasses its rear end and is deposited on the ground as a swath. In both operating modes, the chaff is passed through the straw chopper. In the straw deposit mode, the straw guide plates are placed in a position in which the chaff is distributed across the working width on either side of the swath, but does not reach the region of the swath. In the chopping mode, the straw guide plates are placed in a different position, in which chaff and straw are distributed across the working width of the field.
WO 02/34029 A proposes a combine harvester with a chaff distributor and a straw chopper. The chaff distributor can blow the chaff directly against the straw guide plates, arranged downstream from the straw chopper, so that the chopped straw and the chaff are distributed by the guide plates over the working width. In another operating mode, the straw goes above and bypasses the straw chopper and is deposited as a swath on the field, while the chaff is guided by the chaff distributor along the straw guide plates and is deposited in the field across the working width, at either side of the swath. In additional operating modes, the straw is chopped by the straw chopper and distributed across the working width or deposited in a swath, while the chaff is distributed by the chaff distributor across the working width on either side of the swath. Finally, the possibility is provided of also blowing the chaff into the straw swath in the swath depositing mode.
The brochures “Deutz-Fahr Topliner 8XL,” printer's mark 91 532 01 Printed in Germany 9906, “Case IH Cross-Flow,” printer's mark CF80-D-BR-10/99, and “KP 2000 Straw Chopper Attachment with unique Chaff Blower” of the KPAB company, printer's mark 941523, describe combine harvesters which can likewise be run in a chopping mode and a straw depositing mode. The straw is either delivered through the straw chopper, chopped up, and distributed across the working width (chopping mode), or is taken behind [the chopper] and deposited in a swath in the field (straw mode). In both operating modes, the chaff is delivered to the straw chopper and distributed over the field by the guide plates arranged downstream from the straw chopper.
In the prior art as described in the brochures of the firms Deutz, Case, and KPAB, the chaff is distributed across the working width of the combine in the straw depositing mode. As a result, a portion of the chaff also gets into the straw, which is undesirable for many application areas, such as horse litter. Furthermore, the air stream provided by the straw chopper blows the straw swath up, so that the straw is distributed over a greater width than is desirable for collection with a baling press. The combine described in WO 02/34029 A does not have these drawbacks, but it requires relatively costly chaff distributors. In the combines of DE 100 64 356 A and DE 102 56 744 A, the straw guide plates have to be adjusted in order to switch between the straw depositing mode and the chopping mode, which proves to be relatively cumbersome.